Reagent tube and centrifugally operated solid-liquid separating device

ABSTRACT

A reagent receptacle adapted for mounting in a centrifuge and having a discharge opening positioned for centrifugal discharge of matter therefrom; a filter mounted in the receptacle for filtering the matter discharged; and a normally closed centrifugal force responsive valve controlling flow through the opening.

United States Patent 1 1 Smith 1 3,800,947 [451 Apr. 2, 1974 REAGENTTUBE AND CENTRIFUGALLY OPERATED SOLID-LIQUID SEPARATING DEVICE [76]Inventor: Perry-R. Smith, 6424 Benvenue Ave., Oakland, Calif. 94618 [22]Filed: July 16, 1971 [21] Appl. No.: 163,398

[52] US. Cl 210/117, 210/359, 210/419, 210/DIG. 23

[51] Int. Cl B0ld 33/00 [58] Field of Search 210/83, 84, 97, 117, 136,210/339, 359, 361, 362, 371, 419, 429, DIG.

{56] References Cited UNITED STATES PATENTS 4/1970 Coleman ZlO/DIG. 23

3,300,051 1/1967 Mitchell 210/339 1,076,128 10/1913 Kupfcalc.... 210/1172,854,143 9/1958 Novak 210/361 X 3,661,265 5/1972 Greenspan 210/359Primary Examiner-John Adee Attorney, Agent, or Firm-Warren, Rubin,Brucker & Chickering [57] ABSTRACT A reagent receptacle adapted formounting in a centrifuge and having a discharge opening positioned forcentrifugal discharge of matter therefrom; a filter mounted in thereceptacle for filtering the matter discharged; and a normally closedcentrifugal force responsive valve controlling flow through the opening.

13 Claims, 5 Drawing Figures PATENTEUAPR 2 m4 SHEET 101 2 INVENTOR.

Perry R. Smith BY A! W 5/; bal f Chic/(M ul'g Attorneys The inventionrelates to devices used for separation of solids and liquids bycentrifugation, see US. Pat. Nos. 2,665,008, 2,854,143 and 3,300,051.

In many procedures used in chemical and medical laboratories, variousingredients and/or reagents are required to be mixed together or reactedand subsequently separated, as for example by passing through a filter.Centrifugal filtration is greatly to be desired in those instances whererapid filtration is needed to shorten the length of the procedure andexpedite the return of information to a doctor or other person waitingthereon. Transfer of material from a reagent receptacle to a centrifugalextractor is not always possible or feasible, may be awkward or messy,and may introduce contamination.

An object of the present invention is to provide a combined reagent tubeand centrifugally operated solid-liquid separating device in which thevarious ingredients and reagents may be placed in a reagent receptaclefor interaction or reaction for as long a period as desired, and thenwithout opening the container or requiring transfer of the contentsthereof, the container itself is placed in a centrifuge for rapid andefficient separation of the solid and liquid matter, thus enablingcompletion of the procedure and return of the results thereof in theshortest possible time.

Another object of the present invention is to provide a low-cost,disposable device of the character described which may be manufacturedby low-cost, mass production techniques and furnished in sterilecondition to laboratories for their convenient, one-time use.

REFERRING TO SAID DRAWINGS:

FIG. 1 is a cross sectional view of a reagent tube and centrifugallyoperated solid-liquid separating device constructed in accordance withthe present invention;

FIG. 2 is a cross sectional view of an enlarged scale of the deviceillustrated in FIG. 1 and shown in its cen- Y trifugally orientedposition;

FIG. 3 is a cross sectional view of a modified form of the device;

FIG. 4 is a cross sectional view of a further modified form of thedevice; and

FIG. 5 is a cross sectional view of another modified form of the device.

The combination reagent tube and centrifugally operated solid-liquidseparating device of the present invention comprises briefly a reagenttube or receptacle 11 for receipt of the various ingredients to beoperated upon and which is adapted for mounting in the hinged receivingcup 12 of a centrifuge for whirling in an orbit around the central driveshaft 14 of the centrifuge and for swinging with cup 12 around a hingepin 16 from a normally upright position, as shown in full line in FIG.1, to a horizontal position in the plane of rotation of the centrifuge,as shown in phantom line in FIG. 1 and in full line in FIG. 2. Standardlab oratory centrifuges will comprise a central hub mounted for rotationwith shaft 14, as depicted by arrow 18; a plurality of arms 19 connectedto hub 17 in circumferentially spaced relation and radiating therefrom;and a plurality of test tube receiving cups l2 usually demountablypivoted to arms 19 along horizontal axes provided by pins 16. Pivot pins16 are located adjacent the normally upper ends of cups 12 so that thelatter will depend vertically from pins 16 in the stationary conditionof the centrifuge. Upon rotation of thecentrifuge, cups 12 will swingoutwardly due to centrifugal force as suggested by arrow 21. The balanceof the operating structure of the solidliquid separating device includesa discharge opening 22 in the normally lower end 23 of receptacle 1] inposition for centrifugal discharge of matter 24 in the receptacle whenthe latter is horizontally oriented, as illustrated in FIG. 2; a filter26 mounted in the receptacle for filtering of matter discharged throughopening 22; and a normally closed centrifugal force responsive valve 27controlling flow through opening 22 and having a minimum requiredcentrifugal opening force. The latter function is here provided byspring means 28 for retaining the valve in closed position andpermitting opening of the valve above a predetermined value ofcentrifugal force. As will be observed, the centrifugal force not onlyfunctions to open valve 27 but also to force the liquid component inmatter 24 through filter 26. The normally lower end 31 of the receptacleis formed for receiving the open top 32 of a test tube 33 which is inturn dimensioned for fitting within the mounting cup 12 of thecentrifuge for supporting the apparatus. As here shown, the lower endportion 31 of the receptacle is of reduced cylindrical form so as to fitwithin the open top 32 of test tube 33 and to provide an annularshoulder 34 for supporting test tube end 32 and also forming a supporton the upper end 36 of cup 12.

In the forms of the invention illustrated in FIGS. 1 and 2, and FIG. 3,receptacle 11 is made up of a pair of telescopically mounted, relativelymovable sections 37 and 38. Section 37 is formed with a reagent chamber39 for matter 24 and with end wall 23 and discharge opening 22 therein.Section 38 is formed with an end chamber 41 telescopically receiving thelower end 23 of section 37 and is formed with the reduced cylindricalend 31 for mounting in test tube 33 and supporting cup 12. Valve 27 hereincludes a head 42 mounted interiorly of chamber 39 and is connected toa valve stem 43 mounted for reciprocation through opening 22 formovement of head 42 to and from a valve seat 44 provided by the interiorsurface of end wall 23 surrounding opening 22. Section 38 is formed witha plurality of longitudinally extending passages 46 extending from thebottom wall 47 of chamber 31 to the lower end 31 of the section forconducting liquid into test tube 33. The lower end 51 of valve stem 43is here supported on wall 47 and is enlarged to provide a shoulder orspring rest 52 for one end of helical spring 28, the opposite end of thespring being mounted in compression against the exterior surface 53 ofend wall 23. A light metal spring is all that is required to retain thevalve in normally closed position. Preferably, and

as here shown, valve head 42 is fitted with an O-ring 54 for effectingits sealed engagement against seat 44.

In the form of the invention illustrated in FIGS. 1 and 2, filter 26 ismounted directly against the bottom wall 47 of section 38 and mayconsist ofa disk of filter paper or the like. Wall 47 is preferablybeveled to a cone shape, as illustrated in FIGS. 1 and 2, to vprovide acentral support for stem end 51 which will bear directly upon filter 26,and passages 46 are spaced radially from stem end 51 to prevent blockingof these passages by the stem.

A description of the operation of the device of FIGS. 1 and 2 follows.The ingredients to be mixed and/or reacted are placed in chamber 39 andstirred, agitated, shaken, heated or otherwise treated as required andheld in the chamber for the prescribed period of time. With valve 27closed, the receptacle 1 1 may be treated and handled as any other typeof reagent tube. Of course, the present device has its particularadvantage in those instances where solid and liquid materials placed orformed in chamber 39 are to be separated with either or both of thesolid-liquid materials recovered as a sought end product or for furtherprocessing.

Upon completion of reaction of the materials in chamber 39, the deviceis mounted in the centrifuge as above described and the latter energizedto place the device in rotating orbit. The initial centrifugal forceacting upon the contents of the container and the mass of section 37will be supported by spring 28 maintaining the valve 27 in closedposition. At a predetermined minimum centrifugal force which willcorrespond with a desired speed of rotation of the centrifuge, generallyfrom about 4G0 RPM to 1000 RPM,the operating centrifugal force.willovercome the resistance of spring28 causing section 37 to move intosection 38 and opening of valve 27. The contents of chamber 37 will thenmove due to centrifugal force through opening 22 and onto filter 26. Theliquid phase will be centrifugally compressed through filter 26 andproceed via passages 46 into test tube 33. The solid matter will beretained on the filter and may, where desired, be recovered therefrom.

A modified form of the invention is illustrated in FIG. 3 wherein thehelical metal spring is replaced by a length 28a of lightweight,flexibly resilient, plastic material such as polyvinyl chloride. Suchmaterial can be used safely with most laboratory chemicals, acids, alka-.lies, alcohols, oils and solvents, and may be readily chemicallysterilized. A relatively lightweight, thin wall, resiliently flexibletubing is preferred and is available from several commercial sources, asfor example Van Waters and Rogers, and Gradko Glass Laboratories, Inc.Tube 280 is here mounted around valve stem 43a with its opposite endssupported on ribs 56 on the lower end of the stem and ribs 57 on endwall 23a surrounding discharge opening 22a, ribs 56 and 57 providingspaced rests for holding tube 28a in compression thereby maintainingvalve head 42a on its seat. Under centrifugal force, tube 28a will bowout to foreshorten and permit opening of the valve.

Another feature of the form of the invention illustrated in FIG. 3 isthe disposition of filter 26a for easy removal from the device. As hereshown, the filter is mounted in chamber 390 in spaced opposed relationto head 42a and for engagement by the head and dislodgment of the filterupon axial displacement of valve stem 43a. Preferably, the wall 57 ofsection 37a is formed with an annular shoulder 58 providing a mountingfor filter 26a. The latter may comprise a plastic or metal screen with asheet of filter paper or the like mounted thereon. Upon dislodgment ofthe filter 26a by valve head 42a, the filter may be readily removed withforceps for transfer to a slide, test tube or other procedure. Thefilter should be well fitted about its periphery in chamber 39a so as toprevent leakage of liquid around the edges of the filter and,accordingly, the filter may become jammed in the chamber during thecourse of centrifuging the material through the filter. The spacingbetween filter 26a and valve head 42a is such that the latter willremain spaced from the filter in its normal opening action duringcentrifuging of the material.

The lower end 31a of section 38a is formed as a depending circular skirtfor telescopic insertion into test tube 33a and for providing shoulder34a for supporting the device in the centrifuge.-

A further modified form of the invention is illustrated in FIG. 4wherein the valve spring 28b comprises a plurality of resilient arms 61connected to the upper end 62 of valve stem 43b and extend radially fromthe stem for support on lands provided by the bottom wall 47b of reagentchamber 39b of receptacle 11b. The lower end 51b is here fitted with anO-ring 54b for engagement with the exterior surface 63 of end wall 23bsurrounding discharge opening 22b. Normally, arms 61 will hold valvestem 43b upwardly, as seen in FIG. 4, thereby holding valve 54b sealedagainst seat 63. Under centrifugal force, however, arms 61 will bowdownwardly, as seen' in phantom line in FIG. 4, thereby displacing valve54b from its seat to open position.

In this form of the invention, FIG. 4, receptacle 11b is of a one-piececonstruction, as contrasted to the twosection construction of the formsin FIGS. 1-3, and accordingly the operating mass subject to centrifugalforce is that of the valve itself. This will suffice for mostapplications and provides a simplified, lower-cost construction. Wherestronger sealing force is required, the greater relatively moving massprovided in the twosectional construction may be used. In this form ofthe invention, FIG. 4, the lower end 31b of the one-piece receptacle 11bis formed for insertion into the open end of a test tube and herecomprises an annular depending skirt 66 dimensioned for telescopicinsertion into the test tube and defining the supporting shoulder 34bfunctioning to support the device in a centrifuge as the correspondingshoulder in the first described embodiment. Filter 26b is preferablymounted over the interior end 62 of the valve stem in a manner similarto that shown in FIG. 3 and may be disloged by removing O- ring 54b andpushing valve stem 43b upwardly through opening 22b.

Another form of the invention is illustrated in FIG. 5 wherein theresilient means for retaining the valve in closed position isincorporated in the valve and its seat by forming these parts forresilient retention in closed position and for centrifugal displacementto open position. As here shown, the wall 68 of discharge opening 22c inend wall 230 of receptacle 1 1c is formed with an internal concavesurface not only forming the discharge opening but also a seat for anO-ring 54c mounted on valve stem 43c. O-ring 54c is formed ofresiliently compressible material, such as rubber, and with an externalconvex surface eompressively engaging the interior concave wall 68 inthe closed position of the valve. The application of a predeterminedamount of centrifugal force applied longitudinally of stem 43c willcause valve 54c to pop out of its seat to an open position, as indicatedin phantom line in FIG. 5. The mass of the valve provides such a forceon rotating the device at or above a predetermined speed in thecentrifuge. Stem 43c is here provided with an annular socket 71 at itslower end for retaining of O-ring 540 in position on the stem forsealing the clearance provided between stem 43c and opening 22c. Thissame construction is used in the embodiment in FIG. 4. One or morelaterally extending arms 73 is connected to the upper end of stem 430for engagement with the bottom wall 47c of the chamber for retaining thevalve assembly in the discharge opening when the valve is in openposition. Filter 260 is mounted over the top of the valve stem fordislodgment by removal of O-ring 54c and upward displacement of thevalve stem, as in the case of the embodiment shown in FIG. 4. Also, thelower end 310 of the receptacle is formed with the depending skirt andshoulder for mounting in a test tube and in the centrifuge, as alsoshown in the forms of the invention of FIGS. 3 and 4.

I claim:

1. A centrifugal solid-liquid separation apparatus comprising:

a receptacle having a chamber for receipt of reagents to be mixedtherein and being adapted for mounting in a centrifuge for orbitingtherewith and having an orbiting position;

said receptacle being formed with a discharge opening for said chamberpositioned at the radially outer portion of said receptacle in saidorbiting position;

a filter carried by said receptacle and mounted for filtering thedischarge through said opening;

a valve carried by said receptacle and having a normally seated positionsealing said chamber from said opening and an unseated positioncommunicating said chamber and opening; and

said valve being formed and mounted for responding to a predeterminedmagnitude of centrifugal force developed by said orbiting fordisplacement to an unseated position, thereby centrifugally driving thecontents of said chamber through said filter and discharge opening.

2. An apparatus as defined in claim 1 said receptacle providing a seatfor said valve, said valve and seat being formed for resilient retentionof said valve in seated position and for centrifugal displacement ofsaid valve from said seat to unseated position.

3. An apparatus as defined in claim 2, said receptacle having an annularwall with an internal concave surface forming said discharge opening andsaid seat; and

said valve comprising a ring of resiliently compressible material havingan external convex surface compressibly engaging said concave surface inthe seated position of said valve.

4. An apparatus as defined in claim 3, said valve comprising a stemmounted for axial reciprocation in said opening and for centrifugaldisplacement thercthrough, said stem being formed with an annular socketdemountably receiving said ring.

5. An apparatus as defined in claim 1 and means for supporting saidreceptacle when placed in said centrifuge for relative displacement ofsaid receptacle and means as a function of centrifugal force and beingconnected to said valve for movement thereof to unseated position by andupon said relative displacement. 6. An apparatus as defined in claim 5said receptacle being of elongated form and having said dischargeopening in one end thereof; said means comprising a sectiontelescopically receiving said receptacle for radial outward displacementtherein in said orbiting position; spring means mounted to resist saidoutward displacement of said receptacle; and said valve having a stemengaging said section upon said outward displacement to displace saidvalve to unseated position. 7. An apparatus as defined in claim 6, aliquid receiver demountably secured to said section; and said sectionbeing formed with a passage conducting liquid from said dischargeopening to said receiver.

8. An apparatus as defined in claim 7 said valve having a head mountedin said chamber and said stem extending through said discharge openingto engage said section; said stem and receptacle providing spaced springrests; and said spring means being mounted in compression between saidrests for retaining said valve in normally seated position. I 9. Anapparatus as defined in claim 8, said spring means being of helical formsurrounding said stem portion.

10. An apparatus as defined in claim 8, said spring means comprising atube of flexibly resilient plastic material surrounding said stemportion.

11. An apparatus as defined in claim 1 said filter having a mounting insaid receptacle in spaced opposed relation to said discharge opening;

and said valve being mounted for manual displacement and for engagementwith said filter upon said manual displacement for dislodging saidfilter from said mounting.

12. An apparatus as defined in claim 1 spring means biasing said valveto seated position and comprising a plurality of resilient armsconnected to said valve and supported by said receptacle.

13. An apparatus as defined in claim 12 said valve having a stem mountedthrough said discharge opening;

said arms extending radially from said stem; and

said receptacle being formed with lands supporting the outer ends ofsaid arms.

1. A centrifugal solid-liquid separation apparatus comprising: areceptacle having a chamber for receipt of reagents to be mixed thereinand being adapted for mounting in a centrifuge for orbiting therewithand having an orbiting position; said receptacle being formed with adischarge opening for said chamber positioned at the radially outerportion of said receptacle in said orbiting position; a filter carriedby said receptacle and mounted for filtering the discharge through saidopening; a valve carried by said receptacle and having a normally seatedposition sealing said chamber from said opening and an unseated positioncommunicating said chamber and opening; and said valve being formed andmounted for responding to a predetermined magnitude of centrifugal forcedeveloped by said orbiting for displacement to an unseated position,thereby centrifugally driving the contents of said chamber through saidfilter and discharge opening.
 2. An apparatus as defined in claim 1 saidreceptacle providing a seat for said valve, said valve and seat beingformed for resilient retention of said valve in seated position and forcentrifugal displacement of said valve from said seat to unseatedposition.
 3. An apparatus as defined in claim 2, said receptacle havingan annular wall with an internal concave surface forming said dischargeopening and said seat; and said valve comprising a ring of resilientlycompressible material having an external convex surface compressiblyengaging said concave surface in the seated position of said valve. 4.An apparatus as defined in claim 3, said valve comprising a stem mountedfor axial reciprocation in said opening and for centrifugal displacementtherethrough, said stem being formed with an annular socket demountablyreceiving said ring.
 5. An apparatus as defined in claim 1 and means forsupporting said receptacle when placed in said centrifuge for relativedisplacement of said receptacle and means as a function of centrifugalforce and being connected to said valve for movement thereof to unseatedposition by and upon said relative displacement.
 6. An apparatus asdefined in claim 5 said receptacle being of elongated form and havingsaid discharge opening in one end thereof; said means comprising asection telescopically receiving said receptacle for radial outwarddisplacement therein in said orbiting position; spring means mounted toresist said outward displacement of said receptacle; and said valvehaving a stem engaging said section upon said outward displacement todisplace said valve to unseated position.
 7. An apparatus as defined inclaim 6, a liquid receiver demountably secured to said section; and saidsection being formed with a passage conducting liquid from saiddischarge opening to said receiver.
 8. An apparatus as defined in claim7 said valve having a head mounted in said chamber and said stemextending through said discharge opening to engage said section; saidstem and receptacle providing spaced spring rests; and said spring meansbeing mounted in compression between said rests for retaining said valvein normally seated position.
 9. An apparatus as defined in claim 8, saidspring means being of helical form surrounding said stem portion.
 10. Anapparatus as defined in claim 8, said spring means comprising a tube offlexibly resilient plastic material surrounding said stem portion. 11.An apparatus as defined in claim 1 said filter having a mounting in saidreceptacle in spaced opposed relation to said discharge opening; andsaid valve being mounted for manual displacement and for engagement withsaid filter upon said manual displacement for dislodging said filterfrom said mountIng.
 12. An apparatus as defined in claim 1 spring meansbiasing said valve to seated position and comprising a plurality ofresilient arms connected to said valve and supported by said receptacle.13. An apparatus as defined in claim 12 said valve having a stem mountedthrough said discharge opening; said arms extending radially from saidstem; and said receptacle being formed with lands supporting the outerends of said arms.